Polycarbonate resin is a thermoplastic material that has a heat deflection temperature of about 135° C. or higher and can exhibit superior mechanical properties including impact resistance and excellent self-extinguishing properties, dimensional stability, heat resistance and transparency. Polycarbonate resins are widely used in various applications, such as exterior materials of electronic and electric products, automobile components, and the like.
However, despite excellent transparency and mechanical properties, polycarbonate has limitations in use for exterior materials. When a plastic material is used as an exterior material, the product is often coated to enhance the aesthetics thereof. In this case, a dye diluted with various organic solvents can be applied to the surface of a molded resin article and dried. The organic solvents used as diluents can penetrate into the polycarbonate, which can decrease transparency and mechanical strength. Thus, in order to use polycarbonate in products frequently exposed to various organic solvents in the course of use, it is important for the polycarbonate to have resistance against these organic solvents.
KR Patent Publication No. 2007-0071446, KR Patent Publication No. 2009-0026359 and KR Patent Publication No. 2010-0022376 disclose methods of improving chemical resistance of polycarbonate resins by blending with other resins having chemical resistance. However, while these methods can slightly improve chemical resistance, they can decrease impact resistance. In order to improve impact resistance reduced due to blending, an impact modifier can be used. The impact modifier, however, can significantly decrease transparency of the resin.
JP 05-339390 and U.S. Pat. No. 5,401,826 disclose methods of improving chemical resistance by preparing copolymerized polycarbonate in which a material having chemical resistance is introduced into a conventional polycarbonate resin.
An example of the copolymerized material is 4,4′-bisphenol, which is copolymerized with a polycarbonate resin to improve chemical resistance. However, although 4,4′-bisphenol can improve chemical resistance, it also can reduce impact resistance, thereby deteriorating advantages of the polycarbonate. In particular, as the amount of 4,4′-bisphenol used increases, fluidity drastically decreases, causing deterioration in moldability.